Hello. I have a mint Ruger Super Blackhawk that I got new in 1975 and it hasn't had over 20 rounds put through it.

I don't like the square back grip frame so replaced it with a regular Blackhawk steel frame. It didn't feel right so I changed it back.

Now, when the loading gate is open the cylinder will freely spin in both directions with no clicking sounds at all.

Tonight I stripped it down completely per Ruger's disassembly instructions. I put it all back together and the cylinder still rotates freely in both directions.

I checked the plunger on the base pin and it is fine.

Does anyone have any suggestions? I would appreciate any help.

Sorry...I forgot to say that the transfer bar doesn't entirely cover the firing pin when the hammer is cocked but is however, functional as it should be.

Thanks,
Bill

It it click and spin only one way before you took off the old grip frame?
There are after market hands made to make Rugers do exactly that, but it would have been already installed (obviously) for that to be the "problem" If you send it to Ruger you will get it back with all aftermarket parts removed and replaced with Ruger parts.

^^^

Yes Sir, it did click and spin only one way before I put the Bubba (me) on it.

Ok. Without having the gun in front of me I can only make guesses, but two things I'd look at is #1 the plunger and spring that presses on the cylinder stop. Make use the spring is in the correct position and not bent.
#2 Also look at the hand spring and make sure it's OK too. If the hand spring is not working the hand can retract and the cylinder can spin backwards, but the gun wont work right if you try to cock it pointing the muzzle up. The hand can fall backwards and not rotate the cylinder every time if the spring is mashed or bent.

If the stop spring is messed up the cylinder will not lock right even with the gate closed and can spin backwards and forwards at times, but usually it will be pretty obvious if you press on the cylinder stop with your thumb. (with the cylinder removed of course)

+1 on the hand spring being the problem. On a Blackhawk, the hand spring is a spring loaded plunger in the frame. It is easy to lose the spring and/or plunger when disassembling the gun. Or the plunger could be stuck for some reason. Either way, that's where I would look.